The present invention relates to a lighting system for stage, theater, architectural and display illumination and, more particularly, to a linear effects device for use in a light projection or illumination system.
Conventional theatrical and display lighting systems use various types of patterning discs which are removable insertable into light beams, to modify the distribution of light in the projected beam. For this purpose, a projection gate is often used to form the desired image across the beam of light. Typically, the projection gates are embodied as shutters or etched masks, commonly referred to as xe2x80x9cgobosxe2x80x9d or xe2x80x9cgobo discsxe2x80x9d, that function like stencils in the beam path to project a particular beam configuration or an image pattern. That is, a gobo disc masks the light beam except where a pattern is cut out of the disc, such as star-shaped aperture in the disc.
Known arrangements include rotary assemblies that incorporate several pattern generating elements arranged around an axis of rotation, along with a drive mechanism for rotating a selected pattern into the beam path. Usually several different gobo discs together with optical filters and/or shutters are distributed in respective apertures circumferentially of a carrier wheel or a gobo wheel. The carrier wheel is rotatable to index a desired gobo disc into the path of the light beam.
Also, the selected gobo disc in the carrier wheel may be additionally rotated to project a moving image pattern. For example, U.S. Pat. No. 5,537,303 (Stacy) describes that gobo discs to be rotated may be located in respective gobo holders which have toothed peripheries engaging a sun gear coaxial with a gobo wheel, so that rotation of the sun gear relative to the gobo wheel rotates each gobo disc in its gobo holder.
U.S. Pat. No. 4,891,738 (Richardson et al.) describes that a selected aperture holder (gobo holder) containing a pattern aperture plate and centered on an optical axis may be spun by a holder drive mechanism. Richardson""s holder drive mechanism comprises a motor which is selectively operated in either direction at a selected speed to turn a belt against a rim of the aperture holder and rotate the pattern aperture plate intersected by the light beam around the optical axis.
U.S. Pat. No. 5,739,604 (Summerland) describes using a gobo disc which may be rotated as the rotor of an electric motor. The stator of the motor is provided by coils disposed on a fixed mounting about the rotatable gobo disc. In order to act as the rotor of an electric motor, the periphery of a gobo disc is made magnetically discontinuous by giving it a toothed periphery for a ferrous gobo disc or by placing mutually spaced ferrous inserts at the periphery of a non-ferrous gobo disc.
However, the provision of the toothed gobo discs or toothed gobo holders, bearings, gears or belts to rotate the gobo discs represent a high manufacturing cost which has a considerable impact on the price of lighting or illumination unit as a whole. Moreover, to be effective, these disc rotating mechanisms must function in a densely packed, compact and sometimes highly mobile structure housing both very fragile optical and electronic components together with a light source capable of producing oven-like temperatures. In addition, certain types of lighting instruments are designed to be portable and must withstand truck transport abuses and the vagaries of weather.
Each of the above lighting systems permits only one gobo disc having a single image pattern to be rotated within the path of the light beam. That is, each of the above lighting systems is capable of projecting or illuminating only a single image moving through the projection gate. The present invention proceeds upon the desirability of providing a portable linear effects device to efficiently and inexpensively provide linear effects capabilities in a conventional illumination system.
The linear effects device of the present invention permits a conventional illumination system to project a continuous image through the projection gate, such as clouds moving across the sky. In addition, the present invention enables a conventional illumination system to provide additional linear effects by varying the continuous image projected through the gate, such as changing the shape of the clouds as they move across the sky or modifying the placid clouds into storm clouds. Stated otherwise, the present invention provides linear effects capability to a conventional illumination system by independently rotating two effects discs within the path of the light beam to change the shape of the continuous image pattern or to add shaded areas to the continuous image pattern.
Therefore, it is an object of the present invention to provide an inexpensive linear effects device for independently and simultaneously rotating two effects discs about a single axis for use in a conventional illumination system. The rotation of the second effects disc modifies the continuous image generated by the rotation of the first effects disc.
Another object of this invention is to provide a device which is operable with various types of effects discs, such as metal, plastic or glass effects discs.
A further object of this invention is to provide a device which includes template holders for mounting a static template.
In accordance with this invention, the linear effects device comprises a housing for removably receiving a first effects disc containing a first image pattern and a second effects disc containing a second image pattern therewithin. The housing has first and second ends, each end having an opening to permit a beam of light to pass. The first and second ends being positioned in a beam of light projected by an illumination system such that light enters the housing through the opening in the first end, passes through the two effects discs and exits the housing through the opening in the second end. A first motor is connected to the housing for independently and controllably rotating the first effects disc across a beam of light to project a continuous image of the first image pattern. A second motor is also connected to said housing for independently and controllably rotating the second effects disc to modify the continuous image generated from the first image pattern.
Various other objects, advantages and features of the present invention will become apparent from the ensuing detailed description.